Family, twin and adoption studies have convincingly demonstrated a significant genetic contribution to schizophrenia (1995, Lancet 346: 678-682, and references therein) and have driven studies directed at identification of this genetic component. Schizophrenia is a complex disease and the multifactorial and probable genetic heterogeneity of the condition complicates the application and interpretation of conventional linkage and association studies. At present, however, no specific genes have been described which could play a role in schizophrenia.
Previously, a balanced t(1;11)(q42.1;q14.3) translocation was reported which is linked to schizophrenia and other related mental illness in a large Scottish family (1990, Lancet 336: 13-16) with a maximum LOD of 6.0 (Douglas Blackwood, in preparation). Mapping of the translocation breakpoint on chromosome 11, and the accompanying search for neighbouring genes has already been reported (1997, Am. J. Med. Genet. 74: 82-90, 1998, Pyschiatr. Genet. 8: 175-181). No evidence for the presence of any part of a gene closer than 250 kb to the breakpoint has been found.
It will be clear that there is a great need for the elucidation of genes related to schizophrenia in order to unravel the various roles these genes may play in the disease process. A better knowledge of the genes involved in schizophrenia and the mechanism of action of their encoded proteins might help to create a better insight into the etiology of this psychiatric disorder and its underlying molecular mechanisms. This could eventually lead to improved therapy and better diagnostic procedures.